Orthodontic systems with resilient appliances

ABSTRACT

Systems for moving teeth of a patient&#39;s dental arch from a first tooth arrangement to a second tooth arrangement include a plurality of resilient appliances such as positioning trays or elongated arch members that are used in sequence. Each appliance of the systems includes a row of spaced apart couplings for connection to respective teeth of the dental arch. The appliances have certain geometric characteristics that match the geometric characteristics of other appliances of the system, and at least one appliance has a stiffness that is greater than the stiffness of at least one other appliance.

RELATED APPLICATION DATA

This application is a continuation of application Ser. No. 11/766,524,filed Jun. 21, 2007, which was a continuation of application Ser. No.10/983,457 (U.S. Pat. No. 7,234,936) now issued.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to orthodontic treatment systems whereinresilient appliances are used in sequence to move the patient's teeth todesired orientations in the dental arch.

2. Description of the Related Art

Orthodontic treatment involves movement of malpositioned teeth toimproved orientations. Orthodontic treatment can greatly enhance theaesthetic appearance of the patient's teeth, especially in regions nearthe front of the oral cavity. Orthodontic treatment can also improve thepatient's occlusion so that the teeth function better with each otherduring mastication.

One type of orthodontic treatment is carried out by the use ofelastomeric positioning appliances, also known as repositioning trays oralignment trays. These appliances have overall, generally “U”-shapedconfiguration that generally matches the shape of the patient's dentalarch, and a row of receptacles in the appliance receive respective teethof the dental arch. Some patients favor elastomeric positioningappliances because they can be removed while eating.

Elastomeric positioning appliances are often made by first taking animpression of the patient's dental arches and then making a plaster ofParis or “stone” model from the impression. Next, the teeth of the stonemodel representing the teeth to be moved during treatment are cut orsawn from remaining portions of the model and repositioned as desired,using a wax or other material to hold the repositioned teeth in place. Asheet of thermoplastic material is then placed over the model and heatedsuch that the sheet is formed into the exact shape of the model with therepositioned teeth. Subsequently, edges of the sheet are trimmed asdesired to form a tray. When the tray is set in place over the patient'sdental arch, the elastic characteristics of the thermoplastic materialtend to move the teeth toward the orientations as represented by therepositioned teeth of the model.

A system of elastomeric positioning appliances available from AlignTechnology, Inc. of Santa Clara, Calif. involves a series of alignmenttrays that are used in sequence. The trays are custom-made for eachpatient, and each tray is constructed to move the teeth along anincremental portion of the treatment path. One possible method of makingsuch positioning trays is somewhat similar to the method describedabove, except that a model is provided for each tray of the series andthe teeth are repositioned on each model in accordance with the intendedincremental positions of the patient's teeth along the desired treatmentpath.

Another type of orthodontic treatment is carried out by the use of aseries of tiny, slotted brackets, each of which is affixed to arespective tooth of the patient's dental arch. A resilient arch membersuch as a curved, elongated archwire is placed in the slot of eachbracket. Ends of the archwire are often received in devices known asbuccal tubes that are affixed to the patient's molar teeth. The archwireserves as a track to guide movement of the teeth to desired positions.

SUMMARY OF THE INVENTION

The present invention is directed to novel systems of orthodonticappliances that include a series of resilient appliances for use insequence. Each appliance of the series is constructed to move the teethtoward desired positions and may optionally have a geometry identical tothe geometry of other appliances of the system. However, at least one ofthe appliances is constructed to provide a greater amount of force perunit displacement of tooth movement on at least some of the teeth thanother appliances of the series in order to more efficiently move theteeth to their final positions as the end of the treatment program isapproached.

In more detail, the present invention in one aspect is directed toward asystem for moving teeth of a patient's dental arch from a first tootharrangement to a second tooth arrangement. The system comprises aplurality of resilient trays each having a buccolabial wall section, anocclusal wall section and a lingual wall section. Each tray has a row ofreceptacles for receiving respective teeth of the dental arch of adental patient, and each of the receptacles of each tray is arranged ina certain relative orientation with respect to the remaining receptaclesof the same tray when the tray is relaxed. The relative orientation ofthe receptacles is substantially the same for each of the trays, and atleast one of the trays has a stiffness that is greater than thestiffness of at least one other tray. At least one of the buccolabial,occlusal and lingual wall sections of at least one tray is not incontact with a majority of the buccolabial, occlusal and lingual sidesrespectively of the teeth of the dental patient when received on thedental arch of the patient.

Another aspect of the present invention is also directed to a system formoving teeth of a patient's dental arch from a first tooth arrangementto a second tooth arrangement. This system comprises a plurality ofresilient trays each having a buccolabial wall section, an occlusal wallsection and a lingual wall section. Each tray has a row of receptaclesfor receiving respective teeth of a dental arch of a dental patient, andthe row of receptacles of each tray extends substantially along anarch-shaped curve that is substantially the same for each of the trayswhen the trays are relaxed. At least one tray has a stiffness that isgreater than the stiffness of at least one other tray, and at least oneof the buccolabial, occlusal and lingual wall sections of at least onetray is not in contact with a majority of the buccolabial, occlusal andlingual sides respectively of the teeth of the dental patient whenreceived on the dental arch of the patient.

The present invention is also directed in another aspect toward a systemfor moving teeth of a patient's dental arch from an initial tootharrangement at the beginning of treatment to a final tooth arrangementat the conclusion of treatment. The system comprises a plurality ofresilient trays including an initial tray for receiving the initialtooth arrangement and a final tray for receiving the final tootharrangement. Each tray has a row of receptacles with a buccolabial wallsection and a lingual wall section for receiving respective teeth of thedental arch, and the relative orientation between the receptacles of theinitial tray is substantially the same as the relative orientationbetween the receptacles of the final tray when the initial tray and thefinal tray are relaxed. At least one of the trays has a stiffness thatis greater than the stiffness of at least one other tray. Additionally,at least some of the receptacles of the initial tray of the systemincludes an additional space adjacent at least one of its buccolabialand lingual wall sections, and the additional space lacks an orthodonticappliance when the initial tray is received on the dental arch.

The present invention in another aspect is also directed toward a systemfor moving teeth of a patient's dental arch from an initial tootharrangement at the beginning of treatment to a final tooth arrangementat the conclusion of treatment. The system comprises a plurality ofresilient trays including an initial tray for receiving the initialtooth arrangement and a final tray for receiving the final tootharrangement. Each tray has a row of receptacles with a buccolabial wallsection and a lingual wall section for receiving respective teeth of adental arch, and the row of receptacles of the initial tray and the rowof receptacles of the final tray extend along substantially along thesame arch-shaped curve when the initial and final trays are relaxed. Thefinal tray has a stiffness that is greater than the stiffness of theinitial tray. At least some of the receptacles of the initial tray ofthe system include an additional space adjacent at least one of itsbuccolabial and lingual wall sections, and the additional space lacks anorthodontic appliance when the initial tray is received on the dentalarch.

Optionally, all of the appliances (such as the trays) can be constructedusing standardized or ideal arch forms. Moreover, the couplings of theappliances (such as the tooth receptacles of the trays) may have aconfiguration adapted to receive teeth within a selected range of sizes.Accordingly, the time and expense of designing and constructingcustom-made appliances for each patient can be avoided.

These and other features of the invention are described in more detailin the paragraphs that follow and are illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an inverted perspective view of one resilient appliance of anorthodontic system according to one embodiment of the present invention;

FIG. 2 is a side elevational view of the appliance and the dental archshown in FIG. 1 illustrating the appliance in place over an exemplarydental arch of an orthodontic patient;

FIG. 3 is a bottom view of the appliance and the dental arch illustratedin FIG. 2;

FIG. 4 is a bottom view of an exemplary ideal dental archform,illustrating the location of an embrasure line;

FIG. 5 is a perspective view of one resilient appliance of anorthodontic system according to another embodiment of the invention;

FIG. 6 is a view somewhat similar to FIG. 3 except showing one resilientappliance of an orthodontic system according to yet another embodimentof the invention;

FIG. 7 is a front elevational view of one resilient appliance of anorthodontic system according to still another embodiment of theinvention, showing the appliance coupled to a row of connector membersthat are affixed to respective teeth of an exemplary dental arch of anorthodontic patient;

FIG. 8 is a view somewhat similar to FIG. 7 except that the appliancehas been removed;

FIG. 9 is an enlarged side elevational view of one of the connectormembers alone that is shown in FIGS. 7 and 8;

FIG. 10 is an enlarged side cross-sectional view of the appliance andone of the connector members depicted in FIG. 7, along with the adjacenttooth;

FIG. 11 is a front elevational view of one resilient appliance of anorthodontic system according to yet another embodiment of the invention,illustrating the appliance connected to a row of brackets that areaffixed to teeth of an exemplary dental arch of an orthodontic patient;

FIG. 12 is a perspective view of the appliance alone that is shown inFIG. 11; and

FIG. 13 is an enlarged, fragmentary, front elevational view of a portionof the resilient appliance along with two of the brackets that areillustrated in FIG. 11.

DEFINITIONS

“Mesial” means in a direction toward the center of the patient's curveddental arch.

“Distal” means in a direction away from the center of the patient'scurved dental arch.

“Occlusal” means in a direction toward the outer tips of the patient'steeth.

“Gingival” means in a direction toward the patient's gums or gingiva.

“Buccolabial” means in a direction toward the patient's cheeks or lips.

“Lingual” means in a direction toward the patient's tongue.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A system for moving teeth of a patient's dental arch from a first tootharrangement to a second tooth arrangement comprises a plurality ofresilient appliances that are used in sequence. In the embodimentillustrated in FIGS. 1-3, the appliances comprise trays, and anexemplary tray of the system is broadly designated by the numeral 10. InFIGS. 2 and 3, the tray 10 is shown in use, placed over an exemplarydental arch 12 of an orthodontic patient. The tray 10 is shown alone inFIG. 1.

The tray 10 includes a row of spaced apart couplings or receptacles 14(see FIG. 3), each of which is adapted to connect to and receive arespective tooth 16 of the patient's dental arch. The receptacles 14 arespaced apart from each other along the length of the tray 10, althoughadjoining regions of adjacent receptacles 14 are in communication witheach other.

Each of the receptacles 14 includes at least one wall section 18 that isconstructed to urge the respective tooth toward a desired orientation.In this embodiment, the wall sections 18 include a buccolabial wallsection that extends across and contacts a buccolabial side of the tooth16, a lingual wall section that extends across and contacts a lingualside of the tooth 16 and an occlusal wall section that extends acrossand contacts an occlusal portion of the tooth 16, preferably includingthe outermost occlusal edge of the tooth 16.

In the embodiment of FIGS. 1-3, the inner surfaces of the buccolabialwall section, the lingual wall section and the occlusal wall sectionsmatingly contact and are closely identical in shape to the buccolabialside, the lingual side and the occlusal portion respectively of theteeth 16. The gaps between the wall sections and the adjacent sides ofthe teeth are shown in FIG. 3 only for purposes of illustration, andpreferably are avoided so that the wall sections 18 are in close,complemental contact with the external tooth surfaces.

Each of the receptacles 14 for at least two of the trays of the series,more preferably for at least three trays of the series, and mostpreferably for all of the trays of the series is positioned in a desiredorientation that matches the desired final orientation of the respectivetooth at the conclusion of treatment. For example, in designing the tray10, each tooth 16 has six degrees of freedom of movement. First, eachtooth will have a desired angulation at the conclusion of treatment.Angulation may be defined according to the teachings of Dr. Lawrence A.Andrews as the mesiodistal cant of the facial axis of the clinical crown(“FACC”) relative to a line perpendicular to the occlusal plane (see,e.g., Straight Wire, The Concept and Appliance, by Lawrence F. Andrews(L.A. Wells Co., copyright 1989)). Second, each tooth will also have adesired torque at the conclusion of treatment, and torque may be definedas the buccolabial-lingual cant of the FACC when measured from a lineperpendicular to the occlusal plane. Third, each tooth 16 will have adesired rotation at the conclusion of treatment, and rotation can bedefined as the rotational position of the tooth 16 in an arc about itslong axis. Finally, each tooth 16 may be moved in translation indirections along three reference axes: a mesial-distal reference axis, abuccolabial-lingual reference axis, and an occlusal-gingival referenceaxis.

Optionally, the angulation, torque and crown prominence (i.e. thedistance in a buccolabial direction from the embrasure line to eachcrown's most prominent facial point) of the teeth are identical to theknown preferred values. Examples of suitable preferred values includethose values associated with the treatment philosophies of Dr. Andrewsor of Drs. McLaughlin, Bennett and Trevisi (such as embodied in the“MBT” brand brackets and buccal tubes from 3M Unitek Corporation) as setout in Tables I and II below. Additional information regarding thetreatment philosophies of Drs. McLaughlin, Bennett and Trevisi is setout in their book entitled “Systemized Orthodontic Treatment Mechanics”(Mosby, 2001).

TABLE I Maxillary Arch 1^(st) 2^(nd) 1^(st) 2^(nd) Central LateralCuspid Bicuspid Bicuspid Molar Molar Andrews 2.1 1.65 2.5 2.4 2.5 2.92.9 Crown Prominence, mm Andrews 7 3 −7 −7 −7 −9 −9 torque, degreesAndrews 5 9 11 2 2 5 5 angulation, degrees MBT 17 10 −7, +7 −7 −7 −14−14 torque, or 0 degrees MBT 4 8 8 0 0 0 0 angulation, degrees

TABLE II Mandibular Arch 1^(st) 2^(nd) 1^(st) 2^(nd) Central LateralCuspid Bicuspid Bicuspid Molar Molar Andrews 1.2 1.2 1.9 2.35 2.35 2.52.5 Crown Prominence, mm Andrews −1 −1 −11 −17 −22 −30 −35 torque,degrees Andrews 2 2 5 2 2 2 2 angulation, degrees MBT −6 −6 −6, +6 −12−17 −20 −10 torque, or 0 degrees MBT 0 0 3 2 2 0 0 angulation, degrees

When the tray 10 is relaxed, the geometric orientation of each of thereceptacles 14 matches the desired orientation of the respective tooth16 at the conclusion of treatment. As a consequence, each of thereceptacles 14 when the tray 10 is relaxed has a geometry sufficient tohold the respective tooth 16 in its desired final orientation withdesired angulation, torque, rotation, and translation values, assumingthat the tooth is free to move in space and is not constrained by otherfactors such as restraints imposed by the periodontal ligament and/oralveolar bone.

Optionally, the receptacle 14 does not have a shape that entirelymatches the shape of the exposed portions of the tooth 16. For example,the wall sections 18 may be complemental to and contact the buccolabialand lingual sides of the tooth 16, but may not include an occlusalsection in contact with the occlusal edge of the tooth 16. As anotheroption, the wall sections 18 may include an occlusal wall section forcontact with the occlusal portion of the patient's tooth, but lack abuccolabial or a lingual wall section that is in contact with a majorityof the buccolabial or lingual sides of the tooth 16. However, the wallsections 18 have sufficient area in contact with the tooth 16 to urgethe tooth 16 toward its desired orientation.

Preferably, the receptacles 14 are arranged along a row when the tray 10is relaxed that extends along a predefined arch-shaped reference curvesuch as an ideal embrasure line. An example of an embrasure line isdesignated by the letter “e” in FIG. 4 for the exemplary dental arch 12.The embrasure line is an imaginary curve, located at the level of thetooth crown's midtransverse plane that connects the most facial portionsof the contact areas of all of the tooth crowns in the arch 12 when theteeth 16 are in desired orientations. A variety of embrasure lines arepossible, including embrasure lines that extend along paths offset andparallel to the shapes of commonly available orthodontic archwires.Examples of suitable archwire shapes include the shapes of “OrthoForm ITapered” brand archwires, “OrthoForm II Square” brand archwires and“OrthoForm III Ovoid” brand archwires from 3M Unitek Corporation. Thereceptacles are deemed to extend along the embrasure line when anegative image of the receptacles appears as an image of the teeth whenin desired orientations along the embrasure line.

In the embodiment illustrated in FIGS. 1-3, the outer wall surfaces ofthe tray 10 including the outer surfaces of its buccolabial, occlusaland lingual wall sections are somewhat similar in shape to theunderlying buccolabial, occlusal and lingual surfaces of the dental arch12. This construction is an advantage, in that the volume occupied bythe tray 10 in the oral cavity is reduced. However, other constructionsare also possible. For example, the outer surfaces of the buccolabialand lingual wall sections 18 could extend along respective curves thatfollow in parallel to the embrasure line and lack recessed areascorresponding to the underlying interproximal regions of the dental arch12.

In accordance with the present invention, a system for moving teeth of apatient's dental arch from a first tooth arrangement to a second tootharrangement comprises two or more resilient appliances, and preferablyat least three resilient appliances, such as the trays 10. The trays 10are used in a pre-determined sequence in accordance with the progress ofmovement of the teeth from the first tooth arrangement to the secondtooth arrangement.

Each tooth arrangement is an arrangement of the teeth at some point intime during the course of treatment. As described herein, for example,the first and second arrangements could be the initial and finalarrangements respectively. Alternatively, the first and secondarrangements could be the initial and next subsequent arrangementsrespectively, or the next-to-final and final arrangements respectively.As another alternative, the first and second arrangements could both bearrangements at intermediate points during the course of treatment.

In one embodiment of the invention, at least two trays of the series,more preferably at least three trays of the series and most preferablyall of the trays of the series are identical in appearance when relaxed.Consequently, in this embodiment, the row of receptacles of each traywhen the tray is relaxed extends along the same embrasure line, such asthe embrasure line “e” that is depicted in FIG. 4.

Furthermore, the relative orientation of the receptacles with respect tothe remaining receptacles of the same tray when the tray is relaxed issubstantially the same for each of the trays, and is preferablyidentical for each of the trays. For example, the orientation of areceptacle may be determined by reference to a hypothetical axis that iscollinear with the FACC of the tooth when the tooth is received in thereceptacle. In this example, for instance, the spacing and angularorientation between this hypothetical axis of the receptacle for theupper right lateral tooth and the hypothetical axis of the receptaclefor the upper right cuspid tooth are the same for each tray of thesystem when the trays are relaxed. Similarly, the spacing and angularorientation between other receptacles are the same for each tray of thesystem when the trays are relaxed.

However, at least one of the trays of the series and preferably at leasttwo trays of the series are constructed to provide a greater forceagainst at least some of the teeth for a given dental arch relative tothe force provided against the same teeth by at least one other tray ofthe system. For example, at least one tray has a stiffness that isgreater than the stiffness of at least one other tray. The stiffness maybe varied among the trays by altering the composition or processingconditions of the material used to make the trays, by changing theconstruction of the trays (for example, by changing the thickness of thewall sections 18 in a buccolabial-lingual direction), or by othermethods. The stiffness may be determined by any suitable method, such asthe tensile strength test that is set out in ASTM Test Method D412 forelastomeric materials or the tensile strength test that is set out inASTM Test Method D882 for plastic materials.

Preferably, each tray of the series has a different stiffness, and thetrays are selected so that the stiffness increases as treatmentprogresses. For example, the series may include at least three trays,each having a greater stiffness than the previous tray when used in theproper sequence. In this manner, the trays used in the earlier stages oftreatment, such as the initial tray, provide a relatively light forceper unit displacement on the teeth.

As treatment progresses and as the teeth are moved closer to a desiredtooth arrangement, stiffer trays are utilized. The increased stiffnessof subsequent trays of the system provides additional force on the teethto help ensure that the teeth are moved to their final desiredpositions, even though the amount of remaining necessary tooth movementis relatively small. The increased stiffness also helps to stabilize theteeth and hold the teeth firmly in place without undue movement whilethe teeth are in or near desired final positions. Additionally, theincreased stiffness of subsequent trays of the system helps ensure thatthere is sufficient force to overcome the minimum, threshold forcenecessary to continue movement of the teeth to final positions.

Optionally, all of the trays of the series are made in advance by amanufacturer according to a set of statistical averages or norms. Forexample, data could be gathered from a number of individuals regardingthe size of each tooth, including the thickness of the tooth in abuccolabial-lingual direction, the height of a tooth in anocclusal-gingival direction and the width of a tooth in a mesial-distaldirection. Optionally, the thickness of the tooth is the greatestbuccolabial-lingual thickness taken in a reference plane that passesthrough the facial axis point. The height of the tooth, or cusp height,is measured from the cusp tip to the depth of the central sulcus midwaymesiodistally. The width of the tooth is determined by measuring thegreatest mesiodistal diameter of the tooth.

Next, a number of possible size ranges is developed using statisticalanalysis in order to determine the optimal configuration of each of thereceptacles for the trays of each series. For example, five series oftrays can be developed corresponding to five different ranges of overallarch length as determined along a curved mesial-distal reference axis.Each series includes trays with receptacles adapted to fit a range ofsizes so that, in all likelihood, one tray series and possibly two willinclude trays having receptacles adapted to receive the teeth of anyparticular patient with a relatively close mating fit.

For instance, the gathered tooth data could be analyzed for each toothsuch that the mean tooth height and mean tooth thickness are derived forreceptacles adapted to fit a certain range of tooth widths. Thedimensions of the receptacles that correspond to the tooth heights andtooth thicknesses are then selected to receive the respective teeth inrelatively close complemental relationship for each chosen range oftooth widths. The analysis is repeated for each receptacle of eachseries. Generally speaking, the mean tooth height and mean tooththickness are known to increase and decrease in proportion to theincrease and decrease in tooth width. Consequently, the practitioner canselect the proper series for a best fit from a choice of different,pre-manufactured series based only on a determination of the toothwidths of some or all of the teeth of the patient in need of treatment.

The manufacture and supply of two or more series of trays in advance ofknowing individual patient data (such as the patient's tooth sizes ortype of malocclusion) is a significant advantage, in that themanufacturer and/or practitioner can maintain an inventory of trays inadvance. Once the practitioner has selected a series of trays that bestfit the patient at hand, the first tray of the series can be retrievedfrom inventory for the prompt initiation of treatment. Moreover, theneed to make additional trays once treatment is underway can be avoided,such as in instances in the past where custom-made trays have not movedthe teeth as intended and a mid-course correction with another customtray is needed.

Selection of the proper series of trays for any particular patient canbe carried out by any one of a number of methods. For example, thepractitioner may use manual methods such as calipers to determine theheight, width and/or thickness of each tooth. The practitioner can thenconsult manufacturer's data regarding the various available series oftrays, so that the series providing the best fit can be chosen.

Alternatively, the practitioner may obtain a digital data file regardingthe tooth shapes of the patient. The data file may be obtained by anintra-oral scanner, or by a scanner that scans either an impression ofthe patient's teeth or a model of the patient's teeth. The data file mayinclude data regarding the height, width, thickness, or volume of eachtooth, or any combination of the foregoing. Optionally, this data filemay also include information regarding the shape and/or orientation ofeach tooth. Computer software can then be employed to analyze the dataand select a particular series of trays from a number of differentseries.

For example, the software can select the best series by analyzing thedata regarding tooth widths, and then selecting the series by comparingthe widths of the receptacles of various series to the correspondingwidths of the teeth. As another example, the software can select thebest series by first determining the desired tooth positions at theconclusion of treatment, and then fitting a hypothetical curve to theembrasure line of the teeth at the conclusion of treatment. Thisembrasure line is then compared to the arch-shaped curve along which thereceptacles of the various series extend, in order to select the seriesthat presents a curve that most closely matches the desired embrasureline at the conclusion of treatment. Optionally, the embrasure line usedby the software for purposes of comparison may extend along all of theteeth of the patient's dental arch, or along only a portion of thepatient's dental arch.

Optionally, the manufacturer may assist the practitioner in theselection of the best series of trays. For instance, the practitionermay transmit the tooth data to the manufacturer via the Internet so thatthe manufacturer can use the software mentioned above and, with thepractitioner's approval, promptly ship the selected series to thepractitioner, preferably from an inventory of previously manufacturedtrays. As another alternative, the practitioner can use the softwarementioned above in the practitioner's office or via an interactiveprogram connected by the Internet to the manufacturer's facilities, andpick the best series from an inventory maintained in the practitioner'soffice.

Optionally, the height of one or more of the receptacles in anocclusal-gingival direction may be greater than needed to receive thepatient's tooth at the beginning of use of the tray. Such constructionfacilitates the continued eruption of teeth that have only partiallyerupted and helps ensure that the tray does not hinder the tooth inreaching its full desired height at maturity. In this example, data fora particular patient regarding the height of some of the patient's teethmay be ignored for the purpose of selecting the best series of trays.

As an additional option, the first tray of the series may havereceptacles with additional space adjacent its buccolabial wall sectionor lingual wall section. This additional space is an advantage ininstances where the patient's teeth are significantly crowded at thebeginning of treatment.

Preferably, the trays including the tray 10 are comprised of anaesthetically pleasing material that is resistant to staining by foodand beverages. Preferably, the material is colorless, and preferablytransmits light in the visible wavelengths. Preferably, the materialtransmits sufficient light so that the natural color of the patient'stooth can be observed through the tray.

The trays are preferably made of resilient polymeric materials such aspolyurethane, silicone, latex, fluoropolymer and polyolefin. Examples ofsuitable polyurethane materials include polyester-based materials (suchas Texin 285 brand, Texin 390 brand and Desmopan 453 materials, all fromBayer). Other suitable polyurethane materials include Pellethane brandpolytetramethylene glycol ether nos. 2363-80A, 2363-55D and 2363-62D,all from Dow Chemical. Other suitable polyurethane materials includeTecoflex brand polyether-based material, nos. 80A, 60D and 72D, all fromThemedics.

Suitable silicone materials for the tray include RD 10333 brand siliconefrom RD Rubber, MED-4725 and MED-4755 brand silicone from NuSil, no.50069 silicone from Rhodia Silicones, LIM6071 silicone from GeneralElectric and Baysilone brand silicone, no. LSR 2670 from Bayer. Suitablerubber materials include K-100 natural rubber and K-3800 thermoplasticrubber from Kent Elastomer. Suitable fluoropolymer materials include no.FC 2145 fluoroelastomer from 3M Dyneon.

The trays may comprise a viscoelastic material. As an option, theviscoelastic material can be manually deformed to a permanent orsemipermanent change in configuration by the practitioner so that, forexample, a particular receptacle can be extended in a direction tobetter accommodate a severely malpositioned tooth. Preferably, theviscoelastic material has sufficient inherent memory to urge thereceptacle back toward its original position over a period of time.Preferably, the viscoelastic material exhibits a tan δ in the range ofabout 0.01 to about 2.0, where tan δ is defined as the ratio of theshear loss modulus (G″) to the shear storage modulus (G′) as described,for example, in Viscoelastic Properties of Polymers, by John D. Ferry(third edition, John Wiley and Sons, Inc., copyright 1980).

Optionally, the series of appliances may include other appliances aswell. For example, the series may include two or more identical trayswith the same stiffness. Identical trays may be desired in instanceswhere the tray is replaced with an identical tray after a length oftime, such as in instances where the tray is subject to undue wear or ininstances where the stiffness of the tray significantly changes over aperiod of time. The series of appliances may also include other types ofappliances, such as a brace comprising brackets and an archwire for usein the final stage of treatment and after use of the trays has beenconcluded.

A system for moving teeth of a patient's dental arch according toanother embodiment of the invention also comprises a series of trays,one of which is designated by the numeral 10 a in FIG. 5. The tray 10 aincludes a row of spaced apart couplings or receptacles 14 a, each ofwhich is adapted to receive and connect to a respective tooth of apatient's dental arch.

The tray 10 a is somewhat similar to the tray 10, except that the tray10 a has wall sections 18 a that present a smoothly curved buccolabialsurface and a smoothly curved lingual surface. The buccolabial andlingual surfaces in this embodiment extend in parallel relationship toan embrasure line (not shown in FIG. 5). Such construction providesregions of increased wall section thickness, particularly in regionsadjacent the underlying interproximal areas of the patient's dentalarch. In other aspects, the tray 10 a is essentially the same as thetray 10 described above.

A system for moving teeth of a patient's dental arch according toanother embodiment of the invention comprises a series of trays that isexemplified by the tray 10 b shown in FIG. 6. The tray 10 b includes ashell-like frame 11 b having an overall, generally “U”-shapedconfiguration that is adapted to fit over the dental arch of anorthodontic patient. The frame 11 b also has a generally “U”-shapedconfiguration in cross-sections taken in reference planes perpendicularto the curved central axis of the frame 11 b.

The tray 10 b includes a series of spaced apart wall sections 18 b thatare fixed to the frame 11 b. Some of the wall sections 18 b extend in alingual direction from the buccolabial side of the frame 11 b, while theremaining wall sections 18 b extend in a buccolabial direction from thelingual side of the frame 11 b. Each pair of opposed wall sections 18 bpartially defines a receptacle 14 b for receiving a tooth 16 b of adental arch 12 b.

Optionally, the protruding wall sections 18 b are made of a materialthat is different from the material of the frame 11 b. For example, thewall sections 18 b may be made of a material that has less stiffness orgreater stiffness than the stiffness of the material of the frame 11 b.The wall sections 18 b may also be provided with surface structure suchas a roughened surface that facilitates firm, essentially non-slidingcontact between the wall sections 18 b and the engaged surfaces of thetooth 16 b.

Preferably, the frame 11 b is made of a material that deforms when thetray 10 b is placed over the maloccluded teeth. The inherent resiliencyof the frame 11 b then tends to move the teeth toward desired positions.When the tray 10 is relaxed, the buccolabial and lingual sides of frame11 b preferably follow in parallel along respective curves that areparallel to the desired reference curve such as the embrasure line. Assuch, the configuration of the frame 11 b when the tray is relaxed willmatch the configuration of the frame 11 a once the teeth of the dentalarch 12 b have moved to their desired positions.

Except as described above, the series of trays that includes the tray 10b is essentially the same as the series of trays that includes the tray10 set out above. For example, in one embodiment at least one tray ofthe series of trays that includes the tray 10 b that is having astiffness that is greater than the stiffness of at least one other trayof the same series. The variation in stiffness may be carried out bymodifying that material of the wall sections 18 b, by modifying thematerial of the frame 11 b, by varying the thickness of the wallsections 18 b and/or of the frame 11 b, or by any combination of theforegoing. Moreover, at least two trays of the series that includes thetray 10 b includes a row of the receptacles that extends alongsubstantially the same arch-shaped reference curve such as the embrasureline, and the receptacles are arranged in a certain relative orientationwith respect to remaining receptacles of the same tray when the tray isrelaxed.

A system for moving teeth of a patient's dental arch from a first tootharrangement to a second tooth arrangement according to anotherembodiment of the invention is depicted in FIGS. 7-10 and comprises aplurality of resilient appliances or arch members 22 used in sequence.An exemplary arch member 22 is shown in FIGS. 7 and 10. The arch member22 along with a series of connector members 24 together comprise anorthodontic brace that is broadly designated by the numeral 20.

Each of the connector members 24 is affixed to a respective tooth 26 ofa patient's dental arch 28. In FIGS. 7, 8 and 10, the illustrated dentalarch 28 is an exemplary maxillary or upper dental arch, although itshould be understood in this regard that the brace 20 may be adapted foruse with the mandibular or lower dental arch as well.

FIG. 8 is an illustration somewhat similar to FIG. 7, except that thearch member 22 has been removed. As shown, the connector members 24 aredirectly bonded to the enamel surface of the patient's teeth 26.Preferably, each tooth 26 of the dental arch 28 receives a connectormember 24, although alternative arrangements are also possible. Forexample, the connector members 24 may be attached to all of the teeth 26in the dental arch 28 except for the molar teeth, or may be attached toonly certain selected teeth as may be desired by the practitioner.

FIG. 9 is a side elevational view of the connector member 24 alone. Theconnector member 24 includes a base 30 having an external surface thatis adapted to be directly bonded to the enamel surface of the patient'stooth 26 by an adhesive. Optionally, the external surface of the base 30has a compound concave contour that precisely matches the convexcompound contour of a particular tooth. Optionally, the base 30 isprovided with means for enhancing the bond between the connector member24 and the selected adhesive, such as a roughened or dimpled surface, asurface having particles (irregularly-shaped or regularly-shaped) fixedto the base 30, structure for providing a mechanical interlock with theadhesive when hardened, chemical bond-enhancing means or any combinationof the foregoing.

The connector member 24 includes a body 32 that is connected to the base30. The body 32 has a neck portion 34 that presents an undercut region.The body 32 also includes a bulbous outer head 36 that is connected tothe neck 34.

Preferably, the connector member 24 is made as a single, unitarycomponent such that the body 32 is integrally connected to the base 30.Preferably, the connector member 24 is integrally made of an aestheticmaterial such as a material that is translucent or transparent to lightin the visible wavelengths. As another option, the connector member 24has a color that matches the color of the patient's adjacent dentition.If the connector member 24 is made of a transparent or translucentmaterial, the material preferably transmits sufficient light to enablethe color of the patient's underlying tooth to be visible through thefront or labial side of the connector member 24.

Examples of suitable materials for constructing the connector member 24include ceramic materials, such as single crystal alumina andpolycrystalline alumina. Alternatively, the connector member 24 may bemade of a polymeric material such as polycarbonate. Optionally, thepolymeric material is reinforced with glass fibers. Suitable ceramicmaterials are described, for example, in U.S. Pat. Nos. 4,954,080 and6,648,638. Suitable polymeric materials are described, for example, inU.S. Pat. No. 5,445,770.

The arch member 22 includes a row of couplings or receptacles 38, one ofwhich is designated in FIG. 10. The receptacles 38 are spaced apart fromeach other along the length of the arch member 22. As depicted in FIG.7, each of the receptacles 38 is an opening that receives the head 36 ofa respective connector member 24. Each of the receptacles 38 has aconfiguration adapted to releasably receive the head 36 in snap-fitrelation. Consequently, the arch member 22 can be disconnected from theconnector members 24 when desired.

The exemplary receptacles 38 shown in FIG. 7 surround the head 36 ofeach connector member 24 along the buccolabial, occlusal, mesial,gingival and distal sides of each head 36. However, other constructionsare also possible. For example, the receptacles 38 may extend completelythrough the arch member 22 such that the receptacles 38 compriseapertures and buccolabial sides of the heads 36 are exposed when viewingthe brace 20 in a lingual direction.

The arch member 22 illustrated in FIG. 7 is shown in enlargedcross-sectional view in FIG. 10. In this embodiment, the arch member 22is made of a single layer of polymeric material having sufficientresiliency to receive the connector members 24 in snap-fit relation. Tothis end, the polymeric material deforms to enlarge the opening of thereceptacle 38 as the arch member 22 is urged in a lingual direction inorder to receive the head 36 of the respective connector member 24.

The arch member 22 is preferably made of an aesthetically pleasingmaterial such as translucent, transparent or tooth-colored polymericmaterials. If the arch member 22 is made of a translucent or transparentmaterial, the material preferably transmits sufficient light to enablethe color of the patient's underlying dentition to be visible throughthe front or labial side of the arch member 22. Optionally, reinforcingfibers such as glass fibers can be embedded in the polymeric material ofthe arch member 22. Suitable materials for making the arch member 22include the polymeric materials described above in connection with thetray 10.

Preferably, the arch member 22 is capable of changing from a first statethat facilitates removal and/or installation of the arch member 22 to asecond state that facilitates orthodontic treatment. The change in statemay comprise, for example, a change in material property or a change inshape, and is preferably induced by an environmental change that can becarried out in the patient's oral cavity. The change in state may occurthroughout the arch member 22 or only in selected portions of the archmember 22.

As one example, the arch member 22 may comprise a shape memory polymersuch as “Calo-MER” from Polymer Technology Group, elastic memorycomposite (“EMC”) from Composite Technology Development, Inc. or“Veriflex” from Cornerstone Research Group. These materials have both ahigh and a low temperature transition. For instance, the polymericmaterial may have a lower glass transition temperature that is in therange of about 23° C. to about 37° C., and more preferably in the rangeof about 25° C. to about 35° C., and a higher transition temperaturethat is in the range of about 40° C. to about 50° C. The arch member 22is shaped to conform to a model of the patient's teeth in desiredpositions at a temperature above the higher transition temperature, andthen held in that shape as it is cooled to a temperature below itshigher transition temperature. Next, the arch member 22 is shaped toconform to a model of the patient's teeth in current conditions at atemperature that is between the high and low transition temperature, andheld in that shape while it is cooled to a temperature below the lowertransition temperature. Such construction facilitates the initialconnection of the arch member 22 to the connector members 24, such as ininstances where the initial connection is carried out before the archmember 22 approaches body temperature. If the lower transitiontemperature is between room temperature and body temperature, thematerial will undergo a change in state once the arch member 22 isplaced in the oral cavity and will subsequently provide forces formoving the teeth toward desired positions.

As another example, the arch member 22 may be made of a material thathas a glass transition temperature above body temperature, and is shapedto provide for easy installation or removal at temperatures above itsglass transition temperature. In this example, the arch member 22 iskept at a temperature below its transition temperature beforeinstallation. When it is desired to remove the arch member 22, it iswarmed to a temperature above its glass transition temperature.

Alternatively, the arch member 22 may be constructed of homopolymers,cross-linked homopolymers, copolymers, cross-linked copolymers, orblends thereof with inherent memory as described in U.S. Pat. No.6,183,248. Optionally, the material may have only a single transitiontemperature. To form the memory removal mechanism, these materials maybe formed into a strip that loosely approximates the shape of the arch.Once formed into this arch shape, the strip is shaped at a temperatureabove its transition temperature such that it will deliver desiredforces to the teeth, held in that shape and then cooled to a temperaturebelow its transition temperature. Once the strip is in the mouth,heating the strip above the glass transition temperature will loosen itfrom the appliances. The change in state may also be carried out bymethods other than a temperature change. For instance, the polymericmaterial may change its state when subjected to an aqueous buffersolution having a predetermined pH ratio. Alternatively, the change instate may occur when the polymeric material absorbs liquid as a resultof a change in ionic strength or upon exposure to radiation from asource of light. The change in state may be a change in shape such asexpansion or shrinkage, and may also or in the alternative provide achange in material property such as rigidity (i.e. flexural rigidity) ordurometer hardness.

The change in state may be selected to facilitate reception ordisengagement of the heads 36 in the respective receptacles 38. Forexample, the change in state may provide an enlargement of the openingsto the receptacles 38 when desired, so that less force is needed toinsert the heads 36 in the receptacles. Once the insertion is complete,a reversal of the change in state contracts the openings in order toreduce the probability of unintentional detachment of the heads 36 fromthe arch member 22 during the course of treatment.

Other suitable polymeric materials that undergo a change in state aredescribed in U.S. Pat. Nos. 6,183,248, 5,506,300 and 6,388,043, and U.S.Patent Application Publications Nos. U.S. 2003/0157454 and 2003/0055198.

The arch member 22 may also be made of a multi-component materialcomprising multiple layers. As one example, some of the layers orcomponents could undergo a change in state (such as a glass transition)to reduce the modulus of the arch member 22 for facilitatinginstallation or removal of the arch member 22, while other layers orcomponents remain rigid to help maintain the shape of the arch member22. For instance, one layer may have a transition temperature of about150° C. while a second layer may have a transition temperature of about40° C. Additionally, one or more of the layers could vary in thicknessin different regions along the length of the arch member 22. Examples ofsuitable multi-component materials are described in the above-mentionedU.S. Pat. No. 6,183,248.

The materials described above for making the arch member 22 along withthe methods of constructing the arch member 22 may be used as well formaking trays according to other embodiments of the invention, includingthe tray 10.

Preferably, each arch member 22 of the series has a geometry identicalto the geometry of at least one other, and preferably all of the archmembers of the series. The geometry of the arch member 22 when relaxedcorresponds to the geometry necessary to move the teeth to the desiredfinal positions. When the arch member 22 is placed on the connectormembers 24, however, the geometry of the arch member 22 is changed to atemporary shape corresponding to the shape of the tooth arrangementprior to reaching the desired intermediate or final arrangement, such asthe current tooth arrangement. The resilient properties of the polymericmaterial function to exert forces on the teeth 26 as necessary to shiftthe teeth to the desired intermediate or final arrangement.

As treatment progresses and as the teeth 26 move closer to their desiredfinal positions, the arch member 22 is removed from the connectormembers 24 and replaced with another arch member from the same series.The second arch member has a stiffness that is greater than thestiffness of the first arch member and consequently provides greaterforce on the teeth per unit displacement than the force provided by thefirst arch member. The stiffness may be varied by any of the methodsdescribed above in connection with the trays 10, 10 a, 10 b.

Preferably, the arch member 22 is connected to the connector members 24such that the arch member 22 may exert forces on the connector members24 and hence on the underlying teeth 26 in a number of differentdirections. For example, the arch member 22 can preferably exert forcesas may be needed to move the connector members 24 in either or bothtranslation and rotation with respect to three mutually perpendicularreference axes. As a result, the teeth 26 may be subjected to tipping,torquing or angulation movements as desired. To this end, the heads 36and the receptacles 38 preferably have matching polygonal shapes,matching key and keyway shapes or other interlocking configurations thatfacilitate transmitting the desired forces from the arch member 22 tothe connector members 24 and ultimately to the underlying teeth.

In addition to the arch member 22, or as an alternative, the connectormembers 24 may be made of a material that changes from a first state toa second state, wherein the first state facilitates coupling oruncoupling of the connector members 24 from the arch member 22 and thesecond state facilitate orthodontic treatment. For example, theconnector members 24 may be made of a shape memory material as describedabove, and contracts in shape when cooled in order to ease insertion ofthe heads of the connector members 24 into the receptacles 38.

Additional aspects of the brace 20, including alternative constructionsof the arch member 22 and the connector members 24, are set out inapplicant's pending U.S. patent application entitled “ORTHODONTIC BRACEWITH POLYMERIC ARCH MEMBER”, Ser. No. 10/865,649 filed Jun. 10, 2004.

A system for moving teeth of a patient's dental arch from a first tootharrangement to a second tooth arrangement according to still anotherembodiment of the invention comprises a plurality of resilientappliances or arch members, an exemplary one of which is the arch member40 shown in FIGS. 11-13. In this embodiment, the arch member 40 isconnected to a set of orthodontic brackets 42, each of which is fixed toa corresponding one of the patient's teeth 44. The arch member 40 incombination with the brackets 42 comprises an orthodontic brace that isbroadly designated by the numeral 46.

Examples of suitable brackets 42 are illustrated in enlarged view inFIG. 13. The illustrated brackets 42 are known as a “self-ligating”brackets and are similar to the appliances described in U.S. Pat. Nos.6,302,688 and 6,582,226. Each bracket 42 has an elongated archwire slot50 that extends across the bracket 42 in a generally mesial-distaldirection.

The exemplary self-ligating brackets 42 illustrated in FIGS. 11 and 13have a latch 52 for releasably retaining an archwire or arch member(such as arch member 40) in the archwire slot 50. In this embodiment,the latch 52 comprises a pair of resilient clips 53 having a generally“C”-shaped configuration. Preferably, the clips 53 are sufficientlyflexible to enable the practitioner to insert the arch member 40 in thearchwire slot 50 by pressing the same in a lingual direction such thatthe sides of the clips 53 deflect outwardly and away from each other.Once the arch member 40 is clear of the outer arm portions of the clips53 and is located in the archwire slot 50, the sides of the clips 53self-deflect and spring back toward each other to their normal closedorientation in order to retain the arch member 40 in the archwire slot50.

Preferably, the sides of the clips 53 deflect outwardly in enable thelatch 52 to assume a slot-open orientation and release the arch member40 from the archwire slot 50 whenever the force exerted by the archmember 40 on the bracket 42 exceeds a certain minimum value. Thisminimum value is sufficiently high to prevent the arch member 40 fromunintentionally releasing from the archwire slot 50 during the normalcourse of orthodontic treatment. As such, the arch member 40 can exertforces on the bracket 42 sufficient to carry out the intended treatmentprogram and move the associated tooth as desired. Further details andadditional options for the brackets 42 are set out in the aforementionedU.S. Pat. Nos. 6,302,688 and 6,582,226.

Other types of self-ligating brackets are also possible. For example,the bracket 42 may be identical or similar to the self-ligatingappliances described or referenced in U.S. Pat. Nos. 4,248,588,4,492,573, 4,712,999 and 5,711,666.

As another alternative, the bracket 50 need not be a self-ligatingbracket. For example, the bracket may lack a latch and be provided withtwo or more projections known as “tiewings” that are located on oppositesides of the archwire slot. In practice, the arch member 40 is retainedin the archwire slot of such a bracket by extending a ligature aroundthe tiewings as well as over the arch member 40 in order to retain thelatter in the archwire slot. Suitable ligatures include tiny,elastomeric O-ring ligatures as well as sections of small-diametermetallic wire with ends that are twisted together to form a loop. As yetother options, the brackets may be replaced by buccal tubes or any othertype of tooth-connecting member that has a passage or slot for receivingthe arch member 40.

The arch member 40 is shown alone in FIG. 12. The arch member 40includes an elongated body 54 that is made of a resilient material andhas an overall, generally “U”-shaped configuration in plan view.Optionally, the body 54 when relaxed extends along a reference planethat is parallel to the desired occlusal plane of the patient.

As depicted in FIG. 12, the body 54 includes a series of enlargedsections 56 that are connected together by narrowed sections 58. Asshown, the cross-sectional area of the enlarged section 56 is largerthan the cross-sectional area of the narrowed section 58. Suchconstruction presents a series of couplings or notches 60 that arespaced along the length of the body 54. Each notch 60 extends inwardlyfrom an outer edge of the arch member 40 in a direction toward thecurved, central longitudinal axis of the arch member 40.

In the illustrated embodiment, the notches 60 are located along anocclusal edge (i.e., an edge facing the outer tips of the patient'steeth) of the arch member 40 as well as along a gingival edge (i.e., anedge facing the gums or gingiva of the patient) of the arch member 40.However, other constructions are also possible. For example, thenarrowed sections 58 could be located along the occlusal edge of thearch member 40 such that the notches 60 are only present along thegingival edge of the arch member 40.

In this embodiment, the enlarged sections 56 as well as the narrowedsections 58 have a cross-sectional shape that is generally rectangularwith rounded corners. However, other constructions are also possible.For example, the cross-sectional shapes of the sections 56, 58 may beelliptical, oval or circular. Combinations of such shapes are alsopossible. For example, the enlarged sections 56 may have an oval shapein cross-section, while the narrowed sections 58 may have a generallyrectangular configuration in cross-section. As used herein withreference to the arch member 40, the term “cross-section” means across-section that is generally perpendicular to the curved, centrallongitudinal axis of the arch member 40.

The narrowed sections 58 are received within the archwire slots 50 ofthe bracket 42. To this end, and in this embodiment, the narrowedsections 58 have an overall size or height in an occlusal-gingivaldirection that is less than the occlusal-gingival size or height of thearchwire slot 50. The narrowed sections 58 also have an overallthickness in a buccolabial-lingual direction that is less than thedistance between the bottom or lingual side of the archwire slot 50 andthe outer arm portions of the clip 53 so that the clip 53 may close toretain the arch member 40 once the narrowed section 58 is received inthe archwire slot 50.

Preferably, the cross-sectional configuration of the narrowed section 58is complemental to the cross-sectional configuration of the archwireslot 50. For example, the archwire slot 50 has a rectangular shape, andthe narrowed section 58 has a matching rectangular shape that is justslightly smaller, such as 0.001 inch or 0.025 mm in height and width. Asa result, the narrowed section 58 substantially fills the archwire slot50 and provides good control over movement of the associated toothwithout undue tolerance or “slop”.

The body 54 has a major cross-sectional axis and a minor cross-sectionalaxis when considered in reference planes perpendicular to thelongitudinal axis of the body 54 and between adjacent notches 60. Forexample, the enlarged section 56 of the body 54 has a majorcross-sectional axis that extends in a generally vertical directionviewing FIG. 13, and a minor cross-sectional axis that extends in agenerally horizontal direction viewing FIG. 13. Consequently, the body54 adjacent the notch 60 (i.e., in areas next to the notch 60 in aocclusal-gingival direction) has an overall size or height in anocclusal-gingival direction that is less than the length of the majorcross-sectional axis.

However, the enlarged section 56 of the body 54 need not necessarilyhave a major cross-sectional axis and a minor cross-sectional axis.Instead, the enlarged section 56 may have a vertical cross-sectionalaxis and a horizontal cross-sectional axis that are equal in length. Forexample, the cross-sectional shape of the enlarged section 56 may besquare or circular.

In the embodiment illustrated in FIGS. 11-13, the thickness of the body54 when considered in directions along a buccolabial-lingual referenceaxis is non-uniform along the length of the body 54, such that thethickness of the enlarged sections 56 is greater than the thickness ofthe narrowed sections 58. Other constructions are also possible. Forexample, the enlarged sections 56 may have a thickness that is equal orsubstantially equal to the thickness of the narrowed sections 58 indirections along a buccolabial-lingual reference axis. In other words,the body 54 adjacent the notch 60 may have an overall size in abuccolabial-lingual direction that is the same as the length of theminor cross-sectional axis.

With reference to FIG. 13, each of the notches 60 has a certain width ina mesial-distal direction (i.e., in directions along the length of thedental arch, or along the length or central axis of the body 54). Thewidth of the notches 60 is at least as great as the length of thecorresponding archwire slots 50 (preferably including the space withinthe clips 53) so that the narrowed sections 58 can be received in thearchwire slots 50. In this manner, the notches 60 serve as receptaclesto receive respective brackets 42. Optionally, the width of the notches60 is greater than the length of the archwire slots 50 in order toenable limited, relative sliding movement of the bracket 42 along thelongitudinal axis of the body 54. Alternatively, the width of thenotches 60 is substantially equivalent to the length of the archwireslots 50. As an additional option, the width of some of the notches 60may be substantially equivalent to the length of some of the archwireslots 50, while the width of the remaining notches 60 may be greaterthan the length of the remaining archwire slots 50. Furthermore, thewidth of the notches 60 may vary along the length of the arch member 40in corresponding relation to the variation in width of the respectivebracket 42.

In instances where the brackets 42 are to be mounted on or near themesial-distal center of the respective teeth, the centerline spacingbetween adjacent notches 60 generally corresponds to the centerlinedistance between corresponding, adjacent teeth 44 of the dental arch 45.Consequently, the centerline spacing between adjacent notches 60 alsogenerally corresponds to the centerline distance between corresponding,adjacent brackets 42 located on the dental arch 45. In FIG. 13, thiscenterline spacing between adjacent notches 60 is designated by theletter “d” and preferably is identical or substantially identical to thecenterline spacing between adjacent teeth 44. Preferably, this spacingis identical for each of the arch members of the series.

Preferably, the series of arch members including the arch member 40 fora particular patient is selected from an inventory of pre-manufacturedarch members 40 that are constructed according to a statistical analysissimilar to the analysis described above in connection with the tray 10.For instance, a practitioner may determine the best series of archmembers to use from a set of pre-manufactured series of arch members bymeasuring the width of each of the patient's teeth and then using anumerical analysis to facilitate selection of an optimalpre-manufactured arch member series.

The body 54 of the arch member 40 may be made of any one of a number ofsuitable materials, including the polymeric materials described above inconnection with the tray 10 and the arch member 22 as well as metallicmaterials. Preferred materials include aesthetic polymers such astranslucent, transparent or tooth-colored polymers. Examples of suitablepolymers include polycarbonates, polyurethanes, silicones, latex,fluoropolymer and polyolefins. Optionally, fibers such as glass fiberscan be embedded in the polymeric material. For instance, short fibershaving a length equal to the length of the notches 60 may be placed inthe narrowed sections 58 and oriented in a mesial-distal direction. Asan additional option, one or more metallic wires can be embedded in thepolymeric material, and optionally extend along the entire length of thebody 54.

As another option, the body 54 may comprise a shape memory polymer suchas “Calo-MER” from the Polymer Technology Group, elastic memorycomposite (“EMC”) from Composite Technology Development, Inc. or“Veriflex” from Cornerstone Research Group (“CRG”). As an example, thebody 54 may be made using a shape memory polymer such that the archmember 40 has a shape at room temperature that corresponds to thecurrent shape of the patient's teeth. Once the arch member 40 is placedin the patient's oral cavity and the arch member body 54 rises intemperature to a temperature above its glass transition temperature andto a temperature approximating body temperature, the shape memorycharacteristics of the polymer cause the arch member 40 to move theteeth to desired positions. Such construction facilitates the initialconnection of the arch member 52 to the brackets 54, such as ininstances where the initial connection is carried out before the archmember 52 approaches body temperature.

As yet another option, the body 54 may be made of a metallic materialsuch as stainless steel, nitinol or a cobalt-based nickel alloy. As oneexample, the body 54 may have a coiled configuration similar to theshape of a compression spring to facilitate compression of the body 54in directions along its longitudinal axis. As another example, the bodymay comprise multiple strands of metallic wires that are braided ortwisted together, with openings that are similar to openings of acompression spring to enable compression of the body 54.

Preferably, the arch member 40 is constructed such that the resiliencyof the material of the body 54 provides the desired tooth movementwithout substantial need for relative sliding movement between the archmember 40 and the brackets 42. For example, the arch member 40 may beconstructed so that its shape when relaxed corresponds to the desiredshape of the dental arch 45 when all of the teeth 44 have been moved totheir intended positions, with the notches 60 being arranged to properlylocate each tooth 44 at desired final positions along the dental arch45. This construction helps to avoid problems that are normallyassociated with the sliding mechanics observed between conventionalarchwires and orthodontic appliances, such as friction, bending of thearchwire, gouging of the archwire and the like.

The series of arch members including the arch member 40 are used duringdifferent stages of an orthodontic treatment program for a particularpatient. In particular, the stiffness of the arch members used in thelater stages of treatment are stiffer than the arch members used in theearlier stages of treatment. The variation in stiffness may be providedby changing the composition of the arch member, by changing theprocessing methods used to make the arch member, by changing the shapeof the arch member, or by any combination of the foregoing as well as byother methods as well. However, preferably at least some and morepreferably all of the arch members in any one series have identicalgeometries when relaxed. Other aspects of the series of arch members,such as the relative orientation of the couplings or notches 60, aresimilar to corresponding aspects of the series of trays mentioned above.

All of the patents, patent applications and other publicationsidentified herein are expressly incorporated by reference. Additionally,those skilled in the art will recognize that many modifications andalternative constructions may be made without departing from the essenceof this invention. Accordingly, the invention should not be deemedlimited to the specific embodiments described in detail above, butinstead only by a fair scope of the claims that follow along with theirequivalents.

1. A method for moving teeth of a patient's dental arch from a firsttooth arrangement to a second tooth arrangement comprising: obtaininggeometric information relating to one or more series of resilient trayseach having a buccolabial wall section, an occlusal wall section and alingual wall section, wherein each tray has a row of receptacles forreceiving respective teeth of the dental arch of a dental patient,wherein each of the receptacles of each tray is arranged in a certainrelative orientation with respect to the remaining receptacles of thesame tray when the tray is relaxed, wherein the relative orientation ofthe receptacles is substantially the same for each of the trays, whereinat least one of the trays has a stiffness that is greater than thestiffness of at least one other tray, and wherein at least one of thebuccolabial, occlusal and lingual wall sections of at least one tray isnot in contact with a majority of the buccolabial, occlusal and lingualsides respectively of the teeth of the dental patient when received onthe dental arch of the patient, with the proviso that the plurality ofresilient trays are not created using a model of the dental patient'sdentition; and using the geometric information to select a pre-existingseries from the one or more series of resilient trays.
 2. The method ofclaim 1, wherein the first tooth arrangement is a tooth arrangement atthe beginning of treatment or at an intermediate stage of treatment. 3.The method of claim 1, wherein the second tooth arrangement is a tootharrangement at an intermediate stage of treatment or at the conclusionof treatment.
 4. The method of claim 1, wherein the stiffness of thetrays is varied at least in part by changing the thickness of said atleast one wall section of the buccolabial, occlusal and lingual wallsections.
 5. A method for moving teeth of a patient's dental arch from afirst tooth arrangement to a second tooth arrangement comprising:obtaining geometric information relating to a plurality of resilienttrays each having a buccolabial wall section, an occlusal wall sectionand a lingual wall section, wherein each tray has a row of receptaclesfor receiving respective teeth of a dental arch of a dental patient,wherein the row of receptacles of each tray extends substantially alongan arch-shaped curve that is substantially the same for each of thetrays when the trays are relaxed, wherein at least one tray has astiffness that is greater than the stiffness of at least one other tray,and wherein at least one of the buccolabial, occlusal and lingual wallsections of at least one tray is not in contact with a majority of thebuccolabial, occlusal and lingual sides respectively of the teeth of thedental patient when received on the dental arch of the patient, with theproviso that the trays are not created using a model of the dentalpatient's dentition; and using the geometric information to select apre-existing tray from the plurality of resilient trays.
 6. A methodaccording to claim 5 wherein the first tooth arrangement is a tootharrangement at the beginning of treatment or at an intermediate stage oftreatment.
 7. The method of claim 5, wherein the plurality of resilienttrays comprises at least three trays, wherein the first tootharrangement is a tooth arrangement at the beginning of treatment, andwherein the second tooth arrangement is a tooth arrangement at anintermediate stage of treatment or at the conclusion of treatment. 8.The method of claim 5, wherein the curve is an embrasure line.
 9. Themethod of claim 5, wherein the plurality of resilient trays includes atleast three trays each having a stiffness that is different from thestiffness of other trays of the system.
 10. The method of claim 5,wherein the stiffness of the trays is varied at least in part bychanging the thickness of said at least one wall section of thebuccolabial, occlusal and lingual wall sections.
 11. A method for movingteeth of a patient's dental arch from an initial tooth arrangement atthe beginning of treatment to a final tooth arrangement at theconclusion of treatment comprising: obtaining geometric informationrelating to a plurality of resilient trays including an initial tray forreceiving the initial tooth arrangement and a final tray for receivingthe final tooth arrangement, wherein each tray has a row of receptacleswith a buccolabial wall section and a lingual wall section for receivingrespective teeth of the dental arch, wherein the relative orientationbetween the receptacles of the initial tray is substantially the same asthe relative orientation between the receptacles of the final tray whenthe initial tray and the final tray are relaxed, wherein at least one ofthe trays has a stiffness that is greater than the stiffness of at leastone other tray, wherein at least some of the receptacles of the initialtray of the system include an additional space adjacent at least one ofits buccolabial and lingual wall sections, and wherein the additionalspace lacks an orthodontic appliance when the initial tray is receivedon the dental arch, with the proviso that the plurality of trays are notcreated using a model of the dental patient's dentition; and using thegeometric information to select a pre-existing tray from the pluralityof resilient trays.
 12. The method of claim 11, wherein the row ofreceptacles of at least one tray includes sufficient receptacles toreceive all of the teeth of the dental arch.
 13. The method of claim 11,wherein the receptacles of at least one tray have the same geometry asthe geometry of the corresponding receptacles of at least one other traywhen the trays are relaxed.
 14. The method of claim 11, wherein thestiffness of the trays is varied at least in part by changing thethickness of said at least one wall section of the buccolabial andlingual wall sections.
 15. A method for moving teeth of a patient'sdental arch from an initial tooth arrangement at the beginning oftreatment to a final tooth arrangement at the conclusion of treatmentcomprising: obtaining geometric information relating to a plurality ofresilient trays including an initial tray for receiving the initialtooth arrangement and a final tray for receiving the final tootharrangement, wherein each tray has a row of receptacles with abuccolabial wall section and a lingual wall section for receivingrespective teeth of a dental arch, wherein the row of receptacles of theinitial tray and the row of receptacles of the final tray extendsubstantially along the same arch-shaped curve when the initial andfinal trays are relaxed, wherein the final tray has a stiffness that isgreater than the stiffness of the initial tray, and wherein at leastsome of the receptacles of the initial tray of the system include anadditional space adjacent at least one of its buccolabial and lingualwall sections, and wherein the additional space lacks an orthodonticappliance when the initial tray is received on the dental arch, with theproviso that the plurality of resilient trays are not created using amodel of the dental patient's dentition; and using the geometricinformation to select a pre-existing tray from the plurality ofresilient trays.
 16. The method of claim 15, wherein the receptacles ofat least one tray have the same geometry as the geometry of thecorresponding receptacles of at least one other tray when the trays arerelaxed.
 17. The method of claim 15, wherein the curve is an embrasureline.
 18. The method of claim 15, wherein the plurality of resilienttrays includes at least three trays each having a stiffness that isdifferent from the stiffness of other trays of the system.
 19. Themethod of claim 15, wherein the stiffness of the trays is varied atleast in part by changing the thickness of said at least one wallsection of the buccolabial and lingual wall sections.